I. Field of the Invention
This invention relates generally to a writing instrument with an adjustable shaft and, more specifically, to a writing instrument with a shaft that is originally in the shape of a cylinder and can be molded into an ergonomic shape when the pen point is retrieved for writing, providing a comfortable writing experience.
II. Description of the Prior Art
Heretofore, it is known to construct a writing instrument in the shape of a straight tube and made of hard plastic or metals. A writing instrument of such construction is not ergonomically designed and tends to generate uncomfortable feelings, especially when holders write for a relatively long period of time.
It is also known to construct a writing instrument of which the shape of the shaft is designed ergonomically. Nonetheless, the look of an ergonomically designed writing instrument may not be desirable to consumers.
The present invention improves on the heretofore known writing instrument by providing a pen shaft with variable shapes that offers extended writing comfort as well as stylish pen design.
It is therefore a primary object of the invention to provide a writing instrument having an ergonomically designed shaft with a graceful look. The shaft of the present invention is composed of a barrel, a grip and a head, fitted together by the threaded head. A switch that retrieves and retracts the pen point of the cartridge is installed in the barrel and is connected to a driver. The grip is covered with a soft rubber gripping section.
A few long and narrow holes are located at equal intervals inside the grip close to the threaded head. Near the lower end of the holes are ditches. Vertically positioned support rods are accommodated in the ditches outside the grip. The bottom of the support rods goes into the ditches, and the top of the support rods goes upwards through the holes and sticks out slightly into the threaded head reaching the driver.
As holders click or turn the button for the first time, the switch pushes the cartridge and the driver downwards, and in turn the driver pushes the support rods downwards, making the support rods bend and prop the soft rubber gripping section into the shape of an arch. To undo the action, holders click or turn the button again so that all the components go back to their original positions, and the shaft returns to the shape of a cylinder.